This paper examines empirically the determinants of COVID-19 vaccine rollouts and their effects on health outcomes. We assemble a comprehensive and novel cross-country database at a daily frequency on vaccinations and various health outcomes (new COVID-19 cases, fatalities, intensive care unit (ICU) admissions) for the period December 16, 2020-June 20, 2021. Using this data, we find that: (i) early vaccine procurement, domestic production of vaccines, the severity of the pandemic, a country’s health infrastructure, and vaccine acceptance are significant determinants of the speed of vaccination rollouts; (ii) vaccine deployment significantly reduces new COVID-19 infections, Intensive Care Unit (ICU) admissions, and fatalities, and is more effective when coupled with stringent containment measures, or when a country is experiencing a large outbreak; and (iii) COVID-19 cases in neighboring countries can lead to an increase in a country’s domestic caseload, and hamper efforts in taming its own local outbreak.